Process of making brake-blocks.



to work. for making such ad ustment arises, not from HERBERT FROOD, 0FBUXTON, ENGLAND.

PROCESS OF MAKING BRAKE-BLOCKS.

No Drawing.

Specification of Letters Patent.

Patented May 12, 1914.

Application filed September 4, 1913.. Serial No. 788,458.

To all whom it may concern Be it known that I, HERBERT Fnoon, a subjectof the King of Great Britain and Ireland, and a resident of Buxton, inthe county of Derby, England, have invented certain new and usefulImprovements 1n Processes of Making Brake-Blocks, of which the followingis a specification.

With brake blocks, brake bands, fiat or cone shaped friction clutchrings, or the like consisting of a thick woven fabric similar to drivingbelting and impregnated with cementitious material it is found thatconsiderable and repeated adjustment is necessary for some time afterthe band, block, ring or the like is first put in place and put I havefound that the necessity the wearing away of the fabric, but from itsdiminution in thickness resulting from the working pressure put upon it,which diminution progressively continues, until the fabric has beenreduced to the least thickness it is capable of being reduced to undersuch pressure. When this state is arrived at the fabric composing theband or the like is only further reduced in thickness as a result of thefrictional wear and attrition to which it is subjected, and as the wearis very small very little adjustment is required after the fabric can nolonger be reduced in thickness by the working pressure put upon it.

In carrying this invention into effect such a band, block, ring, or thelike (all of which are included hereinafter in and by a reference to abrake block) has its woven fabric reduced to the required minimumthickness before it is put in use. This minimum thickness may varyaccording to the use to which the brake blockis to be put. but it willbe about or will be less than the thickness to which the woven fabricwould be reduced under the pressure to which it would be duced solely byany working pressure to which it may be later subjected when it is inuse. The pressure is preferably exerted while the brake block is in theform which it willoccupy when in use. The block should be warme tosoften the hard ccmentitious material contained Within it and thepressure be applied while the cementitious material is soft andcomparatively non-resistant. When the pressure is applied to the blockin dies which are shaped to the form the block will have when it is inuse, such dies inclose the block and prevent displacement orlongitudinal extension of the fabric laterally or endwiss whilecompression and reduction of thickness is taking place. Similarly otherdies may also be'shaped to restrain lateral and endwise displacement orextension of the fabric constituting the block or the like duringcompression.

As an example of how much reduction in thickness may be accomplishedaccording to this invention a piece of fabric woven solid tothree-quarters of an inch in thickness may be pressed between dies untilit is only three-eighths of an-inch thick. With blocks so compressedbefore they are put into use all the inconveniences of earlyconsiderable adjustments are avoided.

What I claim is A process of forming a solid hard brake block from athick woven fabric, which consists in impregnating the fabric with acementitious substance which becomes hard under ordinary temperatureconditions,

compressing the woven fabric While the witnesses.

HERBERT FROOD. Witnesses WILLIAM GEO. Hers, JOHN OCoNNnLL.

